#include <stdio.h>

int main() {
    int n = 0;
    int t = 0;
    scanf("%d", &n);
    if (n <= 12) {
        printf("2");
    }
    if (n > 12) {
        int j = n / 12;
        t = 4 * j + 2;
        printf("%d", t);

    }

    return 0;
}